It is known that the natural lens in a human or animal eye can be removed, in particular by phacoemulsification, and replaced by an artificial intraocular lens (IOL). The inserted or implanted intraocular lens must however be attached very precisely in a site-specific manner in order to achieve the desired optical imaging properties and be able to compensate the visual defect of the eye to be corrected in the best possible manner. Here, very different embodiments of intraocular lenses are known. They usually have an optical part and, adjoining thereon, one or more haptic parts. Using these haptic parts or the haptic, the intraocular lens is stabilized in the capsular bag of the eye in terms of position.
During such eye surgery, the anterior capsular bag is cut open, the natural lens core is removed after comminution and the artificial intraocular lens is injected through the cornea via an injector. Since intraocular lenses are made of materials that have a higher refractive power than the human eye tissue, they are very thin compared to the natural lens. Therefore, the aforementioned haptic parts are provided for stabilization purposes. These haptic parts are usually spanned at the equator of the capsular bag and allow the intraocular lens to be positioned in a manner defined in the lateral and axial direction. During the subsequent healing process, the capsular bag shrinks to the intraocular lens and finally ensures the desired long-term stability. The location of the intraocular lens after the healing process is referred to as “effective lens position”. During the simultaneous treatment of cataracts and astigmatism, the ideal target axis for the toric intraocular lens, along which this toric intraocular lens is aligned during surgery, is calculated pre-surgery. An exact long-term alignment of the toric intraocular lens along the target axis is decisive for the success of the simultaneous astigmatism correction.
In respect of the haptic parts, it is known that these open out in a wing-like or sidepiece-like manner at opposite sides of the optical part and project therefrom.
Moreover, options for holding the intraocular lens directly by the anterior capsular bag or for inserting the intraocular lens into the anterior chamber of the eye are also known.
In currently known intraocular lenses, the so-called secondary cataract may occur in the implanted state. A so-called secondary cataract develops in some cases since small remains of the natural lens core often remain in the capsular bag during cataract surgery and these remains are in direct contact with the nutrient liquid of the anterior eye segment. The latter leads to new optical opacification and must therefore likewise be removed or treated. Moreover, the alignment of toric intraocular lenses is already subject to a certain susceptibility to errors during the insertion. The alignment of the toric intraocular lens undertaken by the surgeon during the operation often does not correspond exactly to the calculated ideal alignment. Moreover, the shrinking process of the capsular bag during healing after a cataract operation is subject to natural variations. By way of example, if the capsular bag was not cut open in an exactly circular manner during the operation or if the intraocular lens is not placed concentrically in relation to the capsular bag opening, the final position of the intraocular lens may shift, which is referred to as post-rotation. Since the effective lens position does not correspond to the lens position established in advance, the visual acuity of the patient deteriorates in these embodiments. There is then a significant loss of vision in the case of, in particular, toric and multi-focal high-quality intraocular lenses in these embodiments. This inserted intraocular lens may even have to be removed by surgery again in this case.
Moreover, it should be mentioned that the haptic parts merely serve to stabilize the intraocular lens and therefore represent increased material expenditure which, from a clinical point of view, would not be required in the case of modified intraocular lens stabilization.